2-aryl-polyhalo-bicyclohept-5-enes



7 3378,580 2-ARYL r0LYHALb-mc cLo ErT-s-ENEs Carleton W. Roberts, Midland, and Daniel H. Haigh,

Beaverton; Mich., assignors to The Dow Chemical Company, Mid land, Mich.', a corporation of Delaware NoDrawing: Continuation-impart of application Ser. No.

240,136, Nov. 26, 1962. Thisapplication Mar. 18, 1965,:1.

set: No. 440,913

6 Claims. (Cl. 260 -488) This application is a continuation-in-part of our copending application Ser. No. 240,136, filed Nov. 26, 1962, now abandoned.

This invention relates to organic chemistry, and more particularly to compounds having the formula:

2 Y H Cruz I OX2 Y H2 wherein X represents hydrogen or halogen of atomic Weight less than 50, Y represents halogen of atomic weight of 25 to 100, namely chloro or bromo and Z represents halogen, hydroxy, or a lower alkanoyloxy radical dcriv'd from a monocarboxy-lic lower-alkanoic acid by re-. moval of the active hydrogen from the carboxyl group. A monocarboxylic loweralkanoic acid as here understood contains a total of up to about four carbon atoms,

The present compounds are useful as herbicides, when applied to the foliage of plants that are to be killed. They are useful also as substrates in vapor-phase and gas chromatography columns for discrimination, by differential residence time, between components of a mixture. Added to flammable polymers they reduce flammability and, in sufiicient amount, render the polymers self-extinguishing.

These new compounds may be prepared by the Diels- Alder diene synthesis. The reaction may be simply carried out by causing a reaction of a cyclopentadiene compound of the formula as the diene with, as dien'ophile, an ar-vinylben'zyl com pound of the formula CH2Z Q be,

wherein Z has the values stated herein before, to obtain the adduct product. The reactants are consumed in equimolecular amounts and may thus be supplied to the reaction, It is advantageous but not necessary to use an inert liquid reaction medium, such as xylene, hexane, heptane, octane, nonane, petroleum ether, benzene, toluene, cumene, ethylbenzene, diethylbenzene, ethyltol-uene, chlorobenzene, orth-odichlorobenzene, chlorotoluene, chloroethyl benzene, chloroxylene, and the like, of which the boiling scr'ves'to control the reaction temperature. The

reaction may be carried out at any temperature from together in a reaction vessel whereupon the desired reaction takes placeto some extent. When more rapid rate of reaction is desired, the reactants may be causedto Patented Apr. 16 1968 one *h-our to about 60 hours, with formation of desired product and minor amounts of other substances. The product can be usedin a completely crude form for many of its advantageous uses. When it is desired to recover the desired compound essentially pure, the product of reaction can bedistilled at a su'batmospheric pressurgz stich as about millimeters mercury, absolute, to Ieinove the liquid reaction medium. and thereafter at a lower pressure such as about 0.2 mm., to obtain the essentially pure compound. Other methods of purification known to those skilled in the art, can be applied to the present compounds, for example, fractional crystallization.

Ar-vinylbenzyl compounds which are suitable starting materials include, for example, p-viny-lbenzyl alcohol, mvinylbenzyl chloride, p-vinylbenzyl iodide, o-vinyl'ben-zyl fluoride, o-vinyl benzyl acetate, p-v-inyl benzyl butyrate, and the like.

Suitable dienes include hexachlorocyclopentadiene, 1,2,3,4 tetrachl'orocyclopentadienc, l,2,3,5 tetrabromr 4,4 difiuorocyclopentadiene, hexabromocyclopentad-iene, and the like. Y

The following examples will enable those skillethin the art to practice the present invention.

Example of -(ar-chloromethylphcnyl) fiJJ-hexachlorobicyclo[2.2.1]h t .5

A mixture of 272 grams (1.0 mole) of hexachlorocyclm pentadiene and 500 milliliters toluene is placed in a one liter, round-bottomed flask equipped with heating mantle, dropping funnel and reflux condenser, and heated to reflux temperatures, about -120 C. Thereto, cluring'45 minutes is added, dropwise, 152 grams (1 mole) ar-vinylbenzylchloride. The resulting mixture is heated under re-- flux for 30 hours to prepare the present product. Thereaction mixture is then cooled and filtered to obtain a crude product as residue. The residue solid is recrystalized from Example 2.Prepara tion of 2-(p-chlcromethylphenyl) l,4,5,6,7,7-hexachlorobicyclo[2.2.1]heptene-S I Procedures essentially identical with the foregoing are repeated except that pure p vinylbenzylchloride isused. The resulting pure product melts at 98-98.5 C; Elemental analysis gives values suitable for the compound and the assigned structure is confirmed by infrared spectrum analysis.

In procedures essentially identical with those of EX- ample 1 other vinylbenzyl compounds are caused to re.- act with, a halocyclopentadiene of the stated structure, using any or several of various hydrocarbon and substituted hydrocarbon liquids as solvent. t t

p-Vinylbenzyl alcohol is caused to react with hexaclilorocyclopentadiene in a natural solvent mixture of dichlorobenzenes resulting from the dichlorination of benzene, to prepare a 2-(q-hydroxy-p-tolyl)-l,4,,6,7,7-hexachll%robicycl0-[2.2.ll-hcptene-S as a white crystalline soi In similar procedures but employing 5,5-diehlorol,2,3,4 tetrabromocyclopentadiene and p vinylbenzyl butyrate there is obtained a Z-(a-butyryloxy-p tolyl')- 1,4,5,6-tetrabromo-.7,7 dichlorobicyclo[2.2.llheptane 5 as a white, crystalline solid. The assigned structure is confirmed by infrared analysis. 1

Employing a pwinylbenzyl acetate and 1,2,3,4-tetrachloro-5,5-difluorocyclopentadiene, there is obtained a 2-(a-acetoxy-p-tolyl)-l,4,5,6-tetrachloro 7,7 difiuorobicyclo-[2.2.l]-heptene-5 product as a white crystalline solid.

In similar procedures other products of the present invention are readily prepared.

Illustrative of utility in the present compounds, the compound Z-(ar-chloromethylphenyl)-l,4,5,6,7,7 hexachlorobicyclo[2.2.l]heptene-5 is dispersed in water with the aid of essentially inert co-solvents and wetting agents to prepare an aqueous spray composition comprising the said compound at the rate of 3.3 pounds per hundred gallons of total composition. The application of this dispersion to wet thoroughly all surfaces of leaves and stems of strong young bean plants results in an almost complete kill of the plants.

When employing a compound of the present invention in chromatography, the compound is dissolved in a solvent and the resulting solution thoroughly mixed with a carrier which can be diatomaceous earth, and, thereupon, evaporated to dryness. This obtains a carrier essentially uniformly coated with substrate material and ready for packing, with suction and sonic vibration, into a chromatographic column. A column packed with the said carrier and substrate is useful in vapor phase and gas chromatography. I

When employin a compound of the present invention for fire suppression in a polymer, the compound is incorporated into a polymer. In one manner, not usually preferred, the compound is combined with the monomer which is then polymerized. In another manner, the present compound and polymer are milled together as on opposed co-rotating rollers, one heated and one chilled, the deposited material removed by a doctor blade and returned to the nip of the rollers. Also, both can be dissolved together in a common solvent which is thereafter vaporized and removed. Amounts of the present compound sufficient to introduce halogen in the amount of percent by weight of resulting mixture are se1f extinguishing, with such polymers as polystyrene, ethylene, and the like.

The vinyl'benzyl starting compounds herein are' well known and are described in various references, for example British Patents 792,859 and 792,860.

The halogenated cyclopentadienes appear in, for example, U.S. Patents 2,459,783 and 3,007,958, and in the references therein cited.

We claim:

1. Compound of the formula C HzZ YLlZ/I;

wherein X is selected from hydrogen and halogen of atomic weight less than Y represents chloro or bromo, and Z represents a member of the group consisting of halogen, hydroxy, and loweralkanoyloxy radical derived from a monocarboxylic loweralkanoic acidby removal of the active hydrogen from the carboxyl group, wherein a monocarboxylic loweralkanoic acid as here understood contains a total of up to about four carbon atoms.

2. 2-(ar-chloromethylphenyl) l,4,5,6,7,7 hexachlo- References Cited UNITED STATES PATENTS 2,841,485 7/1958 Johnson et al 2606l8 LORRAINE A. WEINBERGER, Primary Examiner. V. GARNER, Assistant Examiner. 

1. COMPOUNDS OF THE FORMULA 